运行时，
tomcat启动后一切正常，可运行期间会偶尔报空指针（时间间隔较长，异常时，应该也是没有操作的），但对程序的正常运行好像没有影响，具体大大们帮看一下。

---------------------------------------------------
2013-6-2 11:29:32 org.apache.coyote.http11.AbstractHttp11Processor process
严重: Error processing request
java.lang.NullPointerException
        at org.apache.tomcat.util.buf.CharChunk.append(CharChunk.java:355)
        at org.apache.tomcat.util.http.mapper.Mapper.map(Mapper.java:673)
        at org.apache.catalina.connector.CoyoteAdapter.postParseRequest(CoyoteAd
apter.java:646)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:402)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp
11Processor.java:1002)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(
AbstractProtocol.java:585)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin
t.java:1813)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:908)
        at java.lang.Thread.run(Thread.java:619)
2013-6-3 5:15:55 org.apache.coyote.http11.AbstractHttp11Processor process
严重: Error processing request
java.lang.NullPointerException
        at org.apache.tomcat.util.buf.CharChunk.append(CharChunk.java:355)
        at org.apache.tomcat.util.http.mapper.Mapper.map(Mapper.java:673)
        at org.apache.catalina.connector.CoyoteAdapter.postParseRequest(CoyoteAd
apter.java:646)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:402)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp
11Processor.java:1002)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(
AbstractProtocol.java:585)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin
t.java:1813)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:908)
        at java.lang.Thread.run(Thread.java:619)
2013-6-3 11:43:45 org.apache.coyote.ajp.AjpMessage processHeader
严重: Invalid message received with signature 18245
2013-6-3 11:43:45 org.apache.coyote.http11.AbstractHttp11Processor process
严重: Error processing request
java.lang.NullPoi